Belt Lubricant Concentrate

ABSTRACT

The present invention relates to a belt lubricant concentrate comprising 15% by weight to 30% by weight of at least one monocarboxylic acid, 10% by weight to 25% by weight of at least one N-alkyl-1,3-propanediamine, 5% by weight to 15% by weight of at least one nonionic surfactant and water up to 100% by weight.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims benefit of priority under 35 U.S.C.119(a) to European Patent Application No. 22175062.3, filed on May 24,2022, and entitled, “BANDSCHMIERMITTELKONZENTRAT (translation: BeltLubricant Concentrate).” That European patent application isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a belt lubricant concentrate and itsuse in the transport of packages on conveyor belts.

BACKGROUND OF THE INVENTION

Belt lubricants are usually used for the transport of packages, such asbottles or cans, on conveyor belts.

Belt lubricants influence the sliding behaviour of the packages to betransported on conveyor belts. On the one hand, they reduce thecoefficient of friction between the package and the conveyor belt sothat signs of wear on the conveyor belts and the packages to betransported are significantly reduced. However, the friction must be ata minimum so that the packages can be conveyed on the conveyor belt.

Especially in the food industry, conveyor belts often remain in motionwhile the packages transported on them are prevented from beingtransported further by an obstacle (e.g., other packages or baffles).Without suitable belt lubricants, the friction arising thereby wouldlead to increased wear on the packages and the conveyor belts. Inaddition, delays caused by toppled packages could occur in the transportprocess, since the stability of packages located on conveyor belts issignificantly reduced by increased friction between the package and theconveyor belt.

Especially in the food industry, it is furthermore crucial that the beltlubricant used is neither harmful to health nor detrimental to otherhygiene measures (e.g., the use of chlorine dioxide). In addition, it isdesirable to keep the amount of belt lubricant used as low as possiblefor economical and ecological reasons.

It is therefore an object of the present invention to provide a beltlubricant or, respectively, a belt lubricant concentrate which has to beused only in small quantities in order to generate a friction that issuitable for the transport of packages on conveyor belts. Furthermore,it is an object of the present invention that the belt lubricant or,respectively, the belt lubricant concentrate exhibits a lowerconsumption of chlorine dioxide than belt lubricants that are describedin the prior art.

SUMMARY OF THE INVENTION

The present invention therefore relates to a belt lubricant concentratecomprising 15% by weight to 30% by weight of at least one monocarboxylicacid, 10% by weight to 25% by weight of at least oneN-alkyl-1,3-propanediamine, 5% by weight to 15% by weight of at leastone nonionic surfactant and water up to 100% by weight.

Surprisingly, it has been shown that a belt lubricant concentrate havingthe composition according to the invention has particularly advantageousproperties compared to known belt lubricant concentrates. The beltlubricant concentrate according to the invention is sufficiently liquidat application temperatures of between 10 and 35° C. and therefore hasgood processing properties. In addition, it can be mixed with water invery small quantities and still has excellent properties with regard tothe friction value. When diluted in water, the belt lubricantconcentrate according to the invention exhibits a lower consumption ofchlorine dioxide than belt lubricants described in the prior art. Since,in the food industry, chlorine dioxide in the process water is used formicrobiological control, among other things, this is a particularlyadvantageous property of the belt lubricant concentrate according to theinvention with regard to the consumption of chemicals.

A further aspect of the present invention relates to a ready-to-use beltlubricant comprising 0.01% by weight to 0.1% by weight of a beltlubricant concentrate according to the invention and water up to 100% byweight.

The belt lubricant concentrate according to the invention can be used ata concentration of from 0.01% by weight to 0.1% by weight. Before thebelt lubricant is used on industrial plants, the belt lubricantconcentrate according to the invention is diluted with water. The beltlubricant produced in this way can be applied to conveyor belts using awide variety of methods such as, e.g., spray processes.

The low use of belt lubricant concentrate is beneficial in bothecological and economical terms.

Yet another aspect of the present invention relates to the use of a beltlubricant concentrate according to the present invention for chainand/or belt lubrication systems, preferably in the food industry.

The belt lubricant concentrate according to the invention can be usedfor lubricating chain and/or belt lubrication systems.

Another aspect of the present invention relates to a method oflubricating the travel of a container along a conveyor belt, comprisingthe application of a belt lubricant according to the present invention.

DESCRIPTION OF EMBODIMENTS

The belt lubricant concentrate according to the invention comprises 15%by weight to 30% by weight of at least one monocarboxylic acid, 10% byweight to 25% by weight of at least one N-alkyl-1,3-propanediamine, 5%by weight to 15% by weight of at least one nonionic surfactant and waterup to 100% by weight.

According to the invention, it has been shown that the use ofmonocarboxylic acids is particularly advantageous in order to obtain aconcentrate which is sufficiently stable and has a viscosity whichenables further processing into a belt lubricant in a simple manner bymixing with water. It has indeed been shown that the predominant use oforganic acids which have more than one carboxyl group in theconcentration range according to the invention leads to an either solidor viscous concentrate which can hardly be processed further, if at all.In some cases, when a concentrate is diluted with organic acidscomprising more than one carboxyl group, precipitations occur which nolonger allow the diluted concentrate to be reused.

In addition, the selection of the organic acids influences theconsumption of chlorine dioxide, i.e., the degradation of chlorinedioxide over time. The use of organic acids comprising more than onecarboxyl group in belt lubricant concentrates, the latter being dilutedinto belt lubricants, results in a composition which has a higherconsumption of chlorine dioxide than concentrates comprising at leastone monocarboxylic acid. This means that chlorine dioxide in the processwater or in the belt lubricant is degraded more quickly in the presenceof organic acids comprising more than one carboxyl group.

The belt lubricant concentrate according to the invention can compriseone, two, three, four or more different monocarboxylic acids, the use ofone, two or three different monocarboxylic acids being particularlypreferred.

The at least one monocarboxylic acid, the at least oneN-alkyl-1,3-propanediamine and the at least one nonionic surfactant aresupplemented with water to make up 100% by weight, depending on theirconcentration in the final product. The water added can be deionized ordistilled water.

According to a preferred embodiment of the present invention, the atleast one monocarboxylic acid is selected from the group consisting offormic acid and lactic acid.

It has been shown according to the invention that it is particularlyadvantageous to provide formic acid and/or lactic acid in the beltlubricant concentrate according to the invention.

According to another preferred embodiment of the present invention, thealkyl group of the at least one N-alkyl-1,3-propanediamine is a C₁₀-C₂₄alkyl group, preferably a C₁₂-C₂₂ alkyl group, more preferably a C₁₄-C₂₀alkyl group, more preferably a C₁₆-C₂₀ alkyl group, particularly a C₁₈alkyl group.

In order to obtain a suitable friction value for the belt lubricantproduced with the concentrate according to the invention, it isadvantageous to use N-alkyl-1,3-propanediamines whose alkyl group has acertain length range. It has been shown according to the invention thatparticularly good results can be achieved with C₁₀-C₂₄ alkyl groups,with C₁₆-C₂₀ alkyl groups and in particular C₁₈ alkyl groups beingparticularly preferred.

According to yet another preferred embodiment of the present invention,the at least one N-alkyl-1,3-propanediamine isN-octadecyl-propane-1,3-diamine.

According to a preferred embodiment of the present invention, the atleast one nonionic surfactant is a polyalkylene glycol ether, which notonly has a positive effect on lubrication, but also contributes tocleaning by allowing the rubbed-off parts to be flushed out better.

According to a further preferred embodiment of the present invention,the polyalkylene glycol ether has a degree of ethoxylation of between 15and 30, preferably of between 20 and 30, more preferably of between 23and 28, in particular of 25. Lutensol, in particular Lutensol AT25and/or Lutensol FA12K, is used as a particularly preferred polyalkyleneglycol ether.

According to a particularly preferred embodiment of the presentinvention, the concentrate comprises 18% by weight to 28% by weight,preferably 20% by weight to 25% by weight, of the at least onemonocarboxylic acid.

According to a preferred embodiment of the present invention, theconcentrate comprises 12% by weight to 22% by weight, preferably 15% byweight to 20% by weight, of the at least one N-alkyl-1,3-propanediamine.

According to a preferred embodiment of the present invention, theconcentrate comprises 5% by weight to 12% by weight, preferably 7% byweight to 10% by weight, of the at least one nonionic surfactant.

According to a further preferred embodiment of the present invention,the concentrate comprises 10% by weight to 30% by weight, preferably 12%by weight to 25% by weight, of at least one alcohol and/or 5% by weightto 10% by weight, preferably 6% by weight to 8% by weight, of at leastone glycol ether. In some cases, it can be advantageous to adjust theviscosity of the concentrate according to the invention using alcoholor, respectively, glycol ether in the specified amounts. This embodimentis particularly advantageous in applications in which the concentrateaccording to the invention is distributed via pump systems.

The belt lubricant according to the invention comprises 0.01% by weightto 0.1% by weight of a belt lubricant concentrate according to theinvention and water up to 100% by weight. Preferably, the process watercomprises 0.02% by weight to 0.09% by weight, preferably 0.02% by weightto 0.08% by weight, more preferably 0.02% by weight to 0.06% by weight,of the belt lubricant concentrate according to the invention.

The belt lubricant concentrate according to the invention is preferablydiluted with water, preferably with deionized or ion-reduced water,prior to its use. Surprisingly, it has been shown that less of the beltlubricant concentrate according to the invention has to be used thanwith conventional concentrates in order to achieve the same or even abetter friction value. In addition, the belt lubricant according to theinvention is characterized in that it exhibits a lower consumption ofchlorine dioxide than known belt lubricants. This is particularlyadvantageous if the belt lubricant according to the invention is mixedwith chlorine dioxide or used in combination with process watercontaining chlorine dioxide.

According to a preferred embodiment of the present invention, the wateris substantially deionized prior to the introduction of the beltlubricant concentrate according to the invention.

According to a preferred embodiment of the present invention, the beltlubricant comprises 0.01 mg/L to 1 mg/L, preferably 0.01 mg/L to 0.8mg/L, more preferably 0.01 mg/L to 0.5 mg/L, of chlorine dioxide.

Chlorine dioxide is used as a biocide in the food industry, among otherthings.

A further aspect of the present invention relates to the use of a beltlubricant concentrate according to the invention for chain and/or beltlubrication systems, preferably in the food industry.

The belt lubricant concentrate or, respectively, the belt lubricantaccording to the invention is used for chain and/or belt lubricationsystems.

Yet another aspect of the present invention relates to a method oflubricating the travel of a container along a conveyor belt, comprisingthe application of a belt lubricant according to the invention. Methodsof applying belt lubricants to conveyor belts made of steel, forexample, in particular of stainless steel, are well known to thoseskilled in the art. The most common method of applying belt lubricant isthe spray process.

In the method according to the invention, the conveyor belt ispreferably brought into contact with process water which comprises 0.01mg/L to 1 mg/L, preferably 0.01 mg/L to 0.8 mg/L, more preferably 0.01mg/L to 0.5 mg/L, of chlorine dioxide.

Above all, but not only, the control of biological growth (e.g.,bacteria, algae) is of crucial importance in the food industry. Inaddition to physical measures, chemical compounds are usually also usedfor the control of biological growth. A frequently used compound in thisprocess is chlorine dioxide. It has been found that among theingredients of known belt lubricants especially chlorine dioxide isquickly degraded so that the biocidal effect of chlorine dioxide failsto take effect, or does so only to a very limited extent. Surprisingly,it has been found that the belt lubricant according to the inventionexhibits a significantly lower consumption of chlorine dioxide (i.e.,degradation of chlorine dioxide) than previously known belt lubricants.For this reason, the belt lubricant according to the invention isparticularly suitable in industrial plants in which chlorine dioxide isused as a biocide in process water (e.g., pasteurization plants).

The present invention is explained in further detail on the basis of thefollowing examples, but without being restricted to them.

EXAMPLES Example 1: Impact of the Organic Acids and the Acid/Amine Ratioon the Solubility of Belt Lubricant Concentrates

In order to examine the impact of different organic acids and theacid/amine ratio on the solubility of concentrates based onN-alkyl-1,3-propanediamines (e.g., Duomeen O), the followingcompositions were tested:

TABLE 1 Composition #1 #2 #3 #4 #5 #6 #7 Propanediol [g] 31.3 30.1 21.727 19.3 27.7 24.3 Duomeen O [g] 52.1 50.2 36.1 44.9 32.1 40 43.2 Formicacid [g] 13.4 2.2 7.36 9.76 Acetic acid [g] 33 Gluconic acid [g] 14.910.2 Citric acid [g] 42.2 15 Lactic acid [g] 29.4 16.1 Monocarboxylicacids/ 0.3 0.7 0.7 0.5 0.6 0.5 Duomeen O

Compositions 1 to 7 were prepared by mixing the ingredients as indicatedin Table 1. The physical state of the compositions and the solubilityafter mixing with a water/ethanol mixture (2:1) (both at 20° C.) wereexamined. The results are listed in Table 2.

TABLE 2 Physical Mixing ratio state [% by weight] Solubility #1 liquid57.6 non-soluble (precipitates) #2 liquid 59.8 soluble #3 solid 83.1sparingly soluble (yielded a highly viscous mixture) #4 liquid 66.8soluble #5 solid 82 non-soluble #6 liquid 80.1 soluble #7 solid 80non-soluble

As can be seen from Table 2, compositions 3 and 5 were sparingly solubleand non-soluble, respectively. In addition to the monocarboxylic acids,both compositions also contain citric acid, a tricarboxylic acid.Composition 1 was also non-soluble in a water/ethanol mixture (2:1).With this composition, the ratio of formic acid to Duomeen O was 0.3. Incomposition 5, the ratio of organic acids to Duomeen O was 1:1. Sincecomposition 5 was nevertheless non-soluble, the conclusion can be drawnthat both the use of monocarboxylic acids and the ratio of them to theN-alkyl-1,3-propanediamine is essential for the solubility of thecomposition.

Example 2: Determination of the Friction Value of Belt LubricantsProduced from Concentrates of Varying Compositions

The friction value and the viscosity of compositions are crucial fortheir suitability as belt lubricants. In order to examine the impact ofdifferent acids on the friction value and on the viscosity, thefollowing mixtures were prepared:

TABLE 3 Chemical [% by weight] Propanediol 15 Duomeen O 17 Lutensol AT253 Lutensol FA12K 5 Isopropanol 8 Butyl glycol 7 Tributoxyethyl phosphate4 Organic acid 23 Water 18

Formic acid, citric acid, acetic acid and lactic acid were used as theacid.

To determine the friction value, a 0.05% aqueous solution of thecomposition according to Table 3 was sprayed onto conveyor beltsspecially designed for this, using a pump. Approximately 30 litres ofsolution per hour were applied. With the help of a sensor connected to aT-Logg data logger, the measured values could be recorded in theMINISoft V7.18 software from GHM GROUP (Greisinger, Germany). Themeasurement time was 15 minutes, with a measuring point being recordedevery second. By creating a calibration line, the measured signals couldbe converted into the frictional force and consequently the coefficientof friction. The coefficient of friction results from the ratio betweenthe frictional force and the normal force.

For determining the viscosity, the technical rotational viscometerPCE-RVI 2 from PCE Instruments (Germany) comprising the spindle L2 wasused. The viscosity was measured at 20° C. and a spindle speed of 60rpm.

The measured data are represented in the following table:

TABLE 4 Acid Friction value [μR] Viscosity [mPas] Formic acid 0.122 67Citric Acid 0.125 343 Acetic acid 0.123 64 Lactic acid 0.122 76

As can be seen from Table 4, compositions which contain monocarboxylicacids have both low friction values and low viscosities. Compositionswith high viscosities caused the spray nozzles to be clogged after ashort time (less than 10 minutes). The composition containing citricacid had a viscosity which was too high.

Example 3: Impact of the Concentration of N-Alkyl-1,3-Propanediamines onthe Friction Value of Belt Lubricants

The concentration of N-alkyl-1,3-propanediamine in the belt lubricantcan influence the friction value thereof and was therefore examined moreclosely. The composition from Example 2, Table 3, was used, wherein 23%by weight of a monocarboxylic acid was used and was diluted with waterto 100% by weight. The concentration of the components was maintained asoutlined in Table 3, only the content of Duomeen O and the water contentwere adjusted according to Table 5. The friction value and the viscositywere determined analogously to Example 2. The results of themeasurements are illustrated in the following table:

TABLE 5 N-alkyl-1,3-propanediamine Friction value Viscosity [% byweight] [μR] [mPas] 7 0.135 26 15 0.119 59 17 0.121 71 20 0.118 135 230.122 202

It can be seen from Table 5 that the use of less than 7% by weight ofN-alkyl-1,3-propanediamine leads to an increased friction value. Theviscosity increases with the content of N-alkyl-1,3-propanediamine.

Example 4: Degradation Rate of Chlorine Dioxide in the Presence of theBelt Lubricant According to the Invention

The composition of the belt lubricant has a direct impact on thedegradation of chlorine dioxide in an aqueous solution such as processwater.

For determining the consumption of chlorine dioxide, TM CLEAROXID LIQUID(Thonhauser GmbH) was diluted to 2 ppm. 0.05, 0.1 and, respectively,0.2% by weight of belt lubricant concentrate was added to this solution.The content of chlorine dioxide in the solution was determined after 5,10 and 15 minutes by means of the test kit Chlorine Dioxide Test (Merck,Germany) and the photometer Spectroquant Prove 300 (Merck, Germany). Thecomposition according to Table 3 with formic acid as the monocarboxylicacid (SD PLUS) or, respectively, formic acid and lactic acid asmonocarboxylic acids (ratio 2:1) (SD PLUS 2), ECOLAB LUBODRIVE (fromEcolab), ECOLAB DRYEXX (from Ecolab), ECOLAB LUBODRIVE CD (from Ecolab)and water were used as the belt lubricant concentrate. The results ofthe measurements are listed in the following table (BL, belt lubricant):

TABLE 6 BL 0 minutes 5 minutes (conc.) ClO₂ conc. ClO₂ conc. ClO₂decrease [% by weight] [mg/l] [mg/l] [%] SD Plus (0.1) 1.44 1.06 26 SDPlus (0.05) 1.81 1.54 15 Water 1.95 1.65 15 Plus 2 (0.1) 2.14 0.67 51Plus 2 (0.05) 2.34 1.27 28 Ecolab Lubodrive (0.2) 2.08 0.08 96 EcolabLubodrive (0.1) 1.48 0.47 78 Ecolab Lubodrive (0.05) 2.07 1.09 51 EcolabDryexx (0.2) 1.74 0.02 99 Ecolab Dryexx (0.1) 2.18 0.02 99 Ecolab Dryexx(0.05) 2.19 0.06 97 Ecolab Lubodrive CD (0.2) 2.05 0.61 71 EcolabLubodrive CD (0.1) 2.36 0.22 90

TABLE 7 10 minutes 15 minutes BL ClO₂ ClO₂ ClO₂ ClO₂ (conc.) conc.decrease conc. decrease [% by weight] [mg/l] [%] [mg/l] [%] SD Plus(0.1) 0.94 35 0.78 46 SD Plus (0.05) 1.31 28 1.03 43 Water 1.42 27 1.1740 SD Plus 2 (0.1) 0.65 42 0.65 53 SD Plus 2 (0.05) 1.04 39 0.49 49Ecolab Lubodrive (0.2) 0.02 99 0.2 99 Ecolab Lubodrive (0.1) 0.18 920.02 99 Ecolab Lubodrive (0.05) 0.85 65 0.58 79 Ecolab Dryexx (0.2) 0.0299 0.02 99 Ecolab Dryexx (0.1) 0.02 99 0.02 99 Ecolab Dryexx (0.05) 0.0299 0.02 99 Ecolab Lubodrive CD (0.2) 0.26 88 0.08 96 Ecolab Lubodrive CD(0.1) 0.02 99 0.02 99

It can be seen from Tables 6 and 7 that, by using compositions accordingto the invention, the consumption of chlorine dioxide can besignificantly reduced in comparison to compositions not according to theinvention.

1. A belt lubricant concentrate comprising 15% by weight to 30% byweight of at least one monocarboxylic acid, 10% by weight to 25% byweight of at least one N-alkyl-1,3-propanediamine, 5% by weight to 15%by weight of at least one nonionic surfactant and water up to 100% byweight.
 2. The belt lubricant concentrate according to claim 1, whereinthe at least one monocarboxylic acid is selected from the groupconsisting of formic acid, lactic acid, and combinations thereof.
 3. Thebelt lubricant concentrate according to claim 1, wherein the alkyl groupof the at least one N-alkyl-1,3-propanediamine is a C₁₀-C₂₄ alkyl group,a C₁₂-C₂₂ alkyl group, a C₁₄-C₂₀ alkyl group, a C₁₆-C₂₀ alkyl group, ora C₁₈ alkyl group.
 4. The belt lubricant concentrate according to claim1, wherein the at least one N-alkyl-1,3-propanediamine isN-octadecyl-propane-1,3-diamine.
 5. The belt lubricant concentrateaccording to claim 1, wherein the at least one nonionic surfactant is apolyalkylene glycol ether.
 6. The belt lubricant concentrate accordingto claim 5, wherein the polyalkylene glycol ether has a degree ofethoxylation of 15 to
 30. 7. The belt lubricant concentrate according toclaim 1, wherein the concentrate comprises 18% by weight to 28% byweight of the at least one monocarboxylic acid.
 8. The belt lubricantconcentrate according to claim 1, wherein the concentrate comprises 12%by weight to 22% by weight of the at least oneN-alkyl-1,3-propanediamine.
 9. The belt lubricant concentrate accordingto claim 1, wherein the concentrate comprises 5% by weight to 12% byweight of the at least one nonionic surfactant.
 10. The belt lubricantconcentrate according to claim 1, wherein the concentrate furthercomprises 10% by weight to 30% by weight of at least one alcohol and/or5% by weight to 10% by weight of at least one glycol ether.
 11. The beltlubricant concentrate according to claim 1, wherein the water issubstantially deionized.
 12. A belt lubricant comprising 0.01% by weightto 0.1% by weight of the belt lubricant concentrate according to claim 1and lubricant water up to 100% by weight.
 13. The belt lubricantaccording to claim 12, wherein the belt lubricant comprises 0.02% byweight to 0.09% by weight of the belt lubricant concentrate.
 14. Thebelt lubricant according to claim 12, wherein the lubricant water issubstantially deionized.
 15. The belt lubricant according to claim 12,wherein the belt lubricant comprises 0.01 mg/L to 1 mg/L of chlorinedioxide.
 16. A method of lubricating a chain and/or belt lubricationsystem in the food industry, comprising supplying the belt lubricantconcentrate according to claim 1 to the chain and/or belt lubricationsystem.
 17. A method of lubricating the travel of a container along aconveyor belt, comprising applying the belt lubricant according to claim12 to the conveyor belt.
 18. The method according to claim 17, furthercomprising bringing the conveyor belt into contact with process waterwhich comprises 0.01 mg/L to 1 mg/L of chlorine dioxide.